1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_PAGEMAP_H 3 #define _LINUX_PAGEMAP_H 4 5 /* 6 * Copyright 1995 Linus Torvalds 7 */ 8 #include <linux/mm.h> 9 #include <linux/fs.h> 10 #include <linux/list.h> 11 #include <linux/highmem.h> 12 #include <linux/compiler.h> 13 #include <linux/uaccess.h> 14 #include <linux/gfp.h> 15 #include <linux/bitops.h> 16 #include <linux/hardirq.h> /* for in_interrupt() */ 17 #include <linux/hugetlb_inline.h> 18 19 struct folio_batch; 20 21 unsigned long invalidate_mapping_pages(struct address_space *mapping, 22 pgoff_t start, pgoff_t end); 23 24 static inline void invalidate_remote_inode(struct inode *inode) 25 { 26 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || 27 S_ISLNK(inode->i_mode)) 28 invalidate_mapping_pages(inode->i_mapping, 0, -1); 29 } 30 int invalidate_inode_pages2(struct address_space *mapping); 31 int invalidate_inode_pages2_range(struct address_space *mapping, 32 pgoff_t start, pgoff_t end); 33 int write_inode_now(struct inode *, int sync); 34 int filemap_fdatawrite(struct address_space *); 35 int filemap_flush(struct address_space *); 36 int filemap_fdatawait_keep_errors(struct address_space *mapping); 37 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend); 38 int filemap_fdatawait_range_keep_errors(struct address_space *mapping, 39 loff_t start_byte, loff_t end_byte); 40 41 static inline int filemap_fdatawait(struct address_space *mapping) 42 { 43 return filemap_fdatawait_range(mapping, 0, LLONG_MAX); 44 } 45 46 bool filemap_range_has_page(struct address_space *, loff_t lstart, loff_t lend); 47 int filemap_write_and_wait_range(struct address_space *mapping, 48 loff_t lstart, loff_t lend); 49 int __filemap_fdatawrite_range(struct address_space *mapping, 50 loff_t start, loff_t end, int sync_mode); 51 int filemap_fdatawrite_range(struct address_space *mapping, 52 loff_t start, loff_t end); 53 int filemap_check_errors(struct address_space *mapping); 54 void __filemap_set_wb_err(struct address_space *mapping, int err); 55 int filemap_fdatawrite_wbc(struct address_space *mapping, 56 struct writeback_control *wbc); 57 58 static inline int filemap_write_and_wait(struct address_space *mapping) 59 { 60 return filemap_write_and_wait_range(mapping, 0, LLONG_MAX); 61 } 62 63 /** 64 * filemap_set_wb_err - set a writeback error on an address_space 65 * @mapping: mapping in which to set writeback error 66 * @err: error to be set in mapping 67 * 68 * When writeback fails in some way, we must record that error so that 69 * userspace can be informed when fsync and the like are called. We endeavor 70 * to report errors on any file that was open at the time of the error. Some 71 * internal callers also need to know when writeback errors have occurred. 72 * 73 * When a writeback error occurs, most filesystems will want to call 74 * filemap_set_wb_err to record the error in the mapping so that it will be 75 * automatically reported whenever fsync is called on the file. 76 */ 77 static inline void filemap_set_wb_err(struct address_space *mapping, int err) 78 { 79 /* Fastpath for common case of no error */ 80 if (unlikely(err)) 81 __filemap_set_wb_err(mapping, err); 82 } 83 84 /** 85 * filemap_check_wb_err - has an error occurred since the mark was sampled? 86 * @mapping: mapping to check for writeback errors 87 * @since: previously-sampled errseq_t 88 * 89 * Grab the errseq_t value from the mapping, and see if it has changed "since" 90 * the given value was sampled. 91 * 92 * If it has then report the latest error set, otherwise return 0. 93 */ 94 static inline int filemap_check_wb_err(struct address_space *mapping, 95 errseq_t since) 96 { 97 return errseq_check(&mapping->wb_err, since); 98 } 99 100 /** 101 * filemap_sample_wb_err - sample the current errseq_t to test for later errors 102 * @mapping: mapping to be sampled 103 * 104 * Writeback errors are always reported relative to a particular sample point 105 * in the past. This function provides those sample points. 106 */ 107 static inline errseq_t filemap_sample_wb_err(struct address_space *mapping) 108 { 109 return errseq_sample(&mapping->wb_err); 110 } 111 112 /** 113 * file_sample_sb_err - sample the current errseq_t to test for later errors 114 * @file: file pointer to be sampled 115 * 116 * Grab the most current superblock-level errseq_t value for the given 117 * struct file. 118 */ 119 static inline errseq_t file_sample_sb_err(struct file *file) 120 { 121 return errseq_sample(&file->f_path.dentry->d_sb->s_wb_err); 122 } 123 124 /* 125 * Flush file data before changing attributes. Caller must hold any locks 126 * required to prevent further writes to this file until we're done setting 127 * flags. 128 */ 129 static inline int inode_drain_writes(struct inode *inode) 130 { 131 inode_dio_wait(inode); 132 return filemap_write_and_wait(inode->i_mapping); 133 } 134 135 static inline bool mapping_empty(struct address_space *mapping) 136 { 137 return xa_empty(&mapping->i_pages); 138 } 139 140 /* 141 * mapping_shrinkable - test if page cache state allows inode reclaim 142 * @mapping: the page cache mapping 143 * 144 * This checks the mapping's cache state for the pupose of inode 145 * reclaim and LRU management. 146 * 147 * The caller is expected to hold the i_lock, but is not required to 148 * hold the i_pages lock, which usually protects cache state. That's 149 * because the i_lock and the list_lru lock that protect the inode and 150 * its LRU state don't nest inside the irq-safe i_pages lock. 151 * 152 * Cache deletions are performed under the i_lock, which ensures that 153 * when an inode goes empty, it will reliably get queued on the LRU. 154 * 155 * Cache additions do not acquire the i_lock and may race with this 156 * check, in which case we'll report the inode as shrinkable when it 157 * has cache pages. This is okay: the shrinker also checks the 158 * refcount and the referenced bit, which will be elevated or set in 159 * the process of adding new cache pages to an inode. 160 */ 161 static inline bool mapping_shrinkable(struct address_space *mapping) 162 { 163 void *head; 164 165 /* 166 * On highmem systems, there could be lowmem pressure from the 167 * inodes before there is highmem pressure from the page 168 * cache. Make inodes shrinkable regardless of cache state. 169 */ 170 if (IS_ENABLED(CONFIG_HIGHMEM)) 171 return true; 172 173 /* Cache completely empty? Shrink away. */ 174 head = rcu_access_pointer(mapping->i_pages.xa_head); 175 if (!head) 176 return true; 177 178 /* 179 * The xarray stores single offset-0 entries directly in the 180 * head pointer, which allows non-resident page cache entries 181 * to escape the shadow shrinker's list of xarray nodes. The 182 * inode shrinker needs to pick them up under memory pressure. 183 */ 184 if (!xa_is_node(head) && xa_is_value(head)) 185 return true; 186 187 return false; 188 } 189 190 /* 191 * Bits in mapping->flags. 192 */ 193 enum mapping_flags { 194 AS_EIO = 0, /* IO error on async write */ 195 AS_ENOSPC = 1, /* ENOSPC on async write */ 196 AS_MM_ALL_LOCKS = 2, /* under mm_take_all_locks() */ 197 AS_UNEVICTABLE = 3, /* e.g., ramdisk, SHM_LOCK */ 198 AS_EXITING = 4, /* final truncate in progress */ 199 /* writeback related tags are not used */ 200 AS_NO_WRITEBACK_TAGS = 5, 201 AS_LARGE_FOLIO_SUPPORT = 6, 202 }; 203 204 /** 205 * mapping_set_error - record a writeback error in the address_space 206 * @mapping: the mapping in which an error should be set 207 * @error: the error to set in the mapping 208 * 209 * When writeback fails in some way, we must record that error so that 210 * userspace can be informed when fsync and the like are called. We endeavor 211 * to report errors on any file that was open at the time of the error. Some 212 * internal callers also need to know when writeback errors have occurred. 213 * 214 * When a writeback error occurs, most filesystems will want to call 215 * mapping_set_error to record the error in the mapping so that it can be 216 * reported when the application calls fsync(2). 217 */ 218 static inline void mapping_set_error(struct address_space *mapping, int error) 219 { 220 if (likely(!error)) 221 return; 222 223 /* Record in wb_err for checkers using errseq_t based tracking */ 224 __filemap_set_wb_err(mapping, error); 225 226 /* Record it in superblock */ 227 if (mapping->host) 228 errseq_set(&mapping->host->i_sb->s_wb_err, error); 229 230 /* Record it in flags for now, for legacy callers */ 231 if (error == -ENOSPC) 232 set_bit(AS_ENOSPC, &mapping->flags); 233 else 234 set_bit(AS_EIO, &mapping->flags); 235 } 236 237 static inline void mapping_set_unevictable(struct address_space *mapping) 238 { 239 set_bit(AS_UNEVICTABLE, &mapping->flags); 240 } 241 242 static inline void mapping_clear_unevictable(struct address_space *mapping) 243 { 244 clear_bit(AS_UNEVICTABLE, &mapping->flags); 245 } 246 247 static inline bool mapping_unevictable(struct address_space *mapping) 248 { 249 return mapping && test_bit(AS_UNEVICTABLE, &mapping->flags); 250 } 251 252 static inline void mapping_set_exiting(struct address_space *mapping) 253 { 254 set_bit(AS_EXITING, &mapping->flags); 255 } 256 257 static inline int mapping_exiting(struct address_space *mapping) 258 { 259 return test_bit(AS_EXITING, &mapping->flags); 260 } 261 262 static inline void mapping_set_no_writeback_tags(struct address_space *mapping) 263 { 264 set_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 265 } 266 267 static inline int mapping_use_writeback_tags(struct address_space *mapping) 268 { 269 return !test_bit(AS_NO_WRITEBACK_TAGS, &mapping->flags); 270 } 271 272 static inline gfp_t mapping_gfp_mask(struct address_space * mapping) 273 { 274 return mapping->gfp_mask; 275 } 276 277 /* Restricts the given gfp_mask to what the mapping allows. */ 278 static inline gfp_t mapping_gfp_constraint(struct address_space *mapping, 279 gfp_t gfp_mask) 280 { 281 return mapping_gfp_mask(mapping) & gfp_mask; 282 } 283 284 /* 285 * This is non-atomic. Only to be used before the mapping is activated. 286 * Probably needs a barrier... 287 */ 288 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) 289 { 290 m->gfp_mask = mask; 291 } 292 293 /** 294 * mapping_set_large_folios() - Indicate the file supports large folios. 295 * @mapping: The file. 296 * 297 * The filesystem should call this function in its inode constructor to 298 * indicate that the VFS can use large folios to cache the contents of 299 * the file. 300 * 301 * Context: This should not be called while the inode is active as it 302 * is non-atomic. 303 */ 304 static inline void mapping_set_large_folios(struct address_space *mapping) 305 { 306 __set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 307 } 308 309 /* 310 * Large folio support currently depends on THP. These dependencies are 311 * being worked on but are not yet fixed. 312 */ 313 static inline bool mapping_large_folio_support(struct address_space *mapping) 314 { 315 return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && 316 test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); 317 } 318 319 static inline int filemap_nr_thps(struct address_space *mapping) 320 { 321 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 322 return atomic_read(&mapping->nr_thps); 323 #else 324 return 0; 325 #endif 326 } 327 328 static inline void filemap_nr_thps_inc(struct address_space *mapping) 329 { 330 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 331 if (!mapping_large_folio_support(mapping)) 332 atomic_inc(&mapping->nr_thps); 333 #else 334 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 335 #endif 336 } 337 338 static inline void filemap_nr_thps_dec(struct address_space *mapping) 339 { 340 #ifdef CONFIG_READ_ONLY_THP_FOR_FS 341 if (!mapping_large_folio_support(mapping)) 342 atomic_dec(&mapping->nr_thps); 343 #else 344 WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); 345 #endif 346 } 347 348 void release_pages(struct page **pages, int nr); 349 350 struct address_space *page_mapping(struct page *); 351 struct address_space *folio_mapping(struct folio *); 352 struct address_space *swapcache_mapping(struct folio *); 353 354 /** 355 * folio_file_mapping - Find the mapping this folio belongs to. 356 * @folio: The folio. 357 * 358 * For folios which are in the page cache, return the mapping that this 359 * page belongs to. Folios in the swap cache return the mapping of the 360 * swap file or swap device where the data is stored. This is different 361 * from the mapping returned by folio_mapping(). The only reason to 362 * use it is if, like NFS, you return 0 from ->activate_swapfile. 363 * 364 * Do not call this for folios which aren't in the page cache or swap cache. 365 */ 366 static inline struct address_space *folio_file_mapping(struct folio *folio) 367 { 368 if (unlikely(folio_test_swapcache(folio))) 369 return swapcache_mapping(folio); 370 371 return folio->mapping; 372 } 373 374 static inline struct address_space *page_file_mapping(struct page *page) 375 { 376 return folio_file_mapping(page_folio(page)); 377 } 378 379 /* 380 * For file cache pages, return the address_space, otherwise return NULL 381 */ 382 static inline struct address_space *page_mapping_file(struct page *page) 383 { 384 struct folio *folio = page_folio(page); 385 386 if (unlikely(folio_test_swapcache(folio))) 387 return NULL; 388 return folio_mapping(folio); 389 } 390 391 /** 392 * folio_inode - Get the host inode for this folio. 393 * @folio: The folio. 394 * 395 * For folios which are in the page cache, return the inode that this folio 396 * belongs to. 397 * 398 * Do not call this for folios which aren't in the page cache. 399 */ 400 static inline struct inode *folio_inode(struct folio *folio) 401 { 402 return folio->mapping->host; 403 } 404 405 /** 406 * folio_attach_private - Attach private data to a folio. 407 * @folio: Folio to attach data to. 408 * @data: Data to attach to folio. 409 * 410 * Attaching private data to a folio increments the page's reference count. 411 * The data must be detached before the folio will be freed. 412 */ 413 static inline void folio_attach_private(struct folio *folio, void *data) 414 { 415 folio_get(folio); 416 folio->private = data; 417 folio_set_private(folio); 418 } 419 420 /** 421 * folio_change_private - Change private data on a folio. 422 * @folio: Folio to change the data on. 423 * @data: Data to set on the folio. 424 * 425 * Change the private data attached to a folio and return the old 426 * data. The page must previously have had data attached and the data 427 * must be detached before the folio will be freed. 428 * 429 * Return: Data that was previously attached to the folio. 430 */ 431 static inline void *folio_change_private(struct folio *folio, void *data) 432 { 433 void *old = folio_get_private(folio); 434 435 folio->private = data; 436 return old; 437 } 438 439 /** 440 * folio_detach_private - Detach private data from a folio. 441 * @folio: Folio to detach data from. 442 * 443 * Removes the data that was previously attached to the folio and decrements 444 * the refcount on the page. 445 * 446 * Return: Data that was attached to the folio. 447 */ 448 static inline void *folio_detach_private(struct folio *folio) 449 { 450 void *data = folio_get_private(folio); 451 452 if (!folio_test_private(folio)) 453 return NULL; 454 folio_clear_private(folio); 455 folio->private = NULL; 456 folio_put(folio); 457 458 return data; 459 } 460 461 static inline void attach_page_private(struct page *page, void *data) 462 { 463 folio_attach_private(page_folio(page), data); 464 } 465 466 static inline void *detach_page_private(struct page *page) 467 { 468 return folio_detach_private(page_folio(page)); 469 } 470 471 #ifdef CONFIG_NUMA 472 struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order); 473 #else 474 static inline struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order) 475 { 476 return folio_alloc(gfp, order); 477 } 478 #endif 479 480 static inline struct page *__page_cache_alloc(gfp_t gfp) 481 { 482 return &filemap_alloc_folio(gfp, 0)->page; 483 } 484 485 static inline struct page *page_cache_alloc(struct address_space *x) 486 { 487 return __page_cache_alloc(mapping_gfp_mask(x)); 488 } 489 490 static inline gfp_t readahead_gfp_mask(struct address_space *x) 491 { 492 return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN; 493 } 494 495 typedef int filler_t(void *, struct page *); 496 497 pgoff_t page_cache_next_miss(struct address_space *mapping, 498 pgoff_t index, unsigned long max_scan); 499 pgoff_t page_cache_prev_miss(struct address_space *mapping, 500 pgoff_t index, unsigned long max_scan); 501 502 #define FGP_ACCESSED 0x00000001 503 #define FGP_LOCK 0x00000002 504 #define FGP_CREAT 0x00000004 505 #define FGP_WRITE 0x00000008 506 #define FGP_NOFS 0x00000010 507 #define FGP_NOWAIT 0x00000020 508 #define FGP_FOR_MMAP 0x00000040 509 #define FGP_HEAD 0x00000080 510 #define FGP_ENTRY 0x00000100 511 #define FGP_STABLE 0x00000200 512 513 struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, 514 int fgp_flags, gfp_t gfp); 515 struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, 516 int fgp_flags, gfp_t gfp); 517 518 /** 519 * filemap_get_folio - Find and get a folio. 520 * @mapping: The address_space to search. 521 * @index: The page index. 522 * 523 * Looks up the page cache entry at @mapping & @index. If a folio is 524 * present, it is returned with an increased refcount. 525 * 526 * Otherwise, %NULL is returned. 527 */ 528 static inline struct folio *filemap_get_folio(struct address_space *mapping, 529 pgoff_t index) 530 { 531 return __filemap_get_folio(mapping, index, 0, 0); 532 } 533 534 /** 535 * filemap_lock_folio - Find and lock a folio. 536 * @mapping: The address_space to search. 537 * @index: The page index. 538 * 539 * Looks up the page cache entry at @mapping & @index. If a folio is 540 * present, it is returned locked with an increased refcount. 541 * 542 * Context: May sleep. 543 * Return: A folio or %NULL if there is no folio in the cache for this 544 * index. Will not return a shadow, swap or DAX entry. 545 */ 546 static inline struct folio *filemap_lock_folio(struct address_space *mapping, 547 pgoff_t index) 548 { 549 return __filemap_get_folio(mapping, index, FGP_LOCK, 0); 550 } 551 552 /** 553 * find_get_page - find and get a page reference 554 * @mapping: the address_space to search 555 * @offset: the page index 556 * 557 * Looks up the page cache slot at @mapping & @offset. If there is a 558 * page cache page, it is returned with an increased refcount. 559 * 560 * Otherwise, %NULL is returned. 561 */ 562 static inline struct page *find_get_page(struct address_space *mapping, 563 pgoff_t offset) 564 { 565 return pagecache_get_page(mapping, offset, 0, 0); 566 } 567 568 static inline struct page *find_get_page_flags(struct address_space *mapping, 569 pgoff_t offset, int fgp_flags) 570 { 571 return pagecache_get_page(mapping, offset, fgp_flags, 0); 572 } 573 574 /** 575 * find_lock_page - locate, pin and lock a pagecache page 576 * @mapping: the address_space to search 577 * @index: the page index 578 * 579 * Looks up the page cache entry at @mapping & @index. If there is a 580 * page cache page, it is returned locked and with an increased 581 * refcount. 582 * 583 * Context: May sleep. 584 * Return: A struct page or %NULL if there is no page in the cache for this 585 * index. 586 */ 587 static inline struct page *find_lock_page(struct address_space *mapping, 588 pgoff_t index) 589 { 590 return pagecache_get_page(mapping, index, FGP_LOCK, 0); 591 } 592 593 /** 594 * find_or_create_page - locate or add a pagecache page 595 * @mapping: the page's address_space 596 * @index: the page's index into the mapping 597 * @gfp_mask: page allocation mode 598 * 599 * Looks up the page cache slot at @mapping & @offset. If there is a 600 * page cache page, it is returned locked and with an increased 601 * refcount. 602 * 603 * If the page is not present, a new page is allocated using @gfp_mask 604 * and added to the page cache and the VM's LRU list. The page is 605 * returned locked and with an increased refcount. 606 * 607 * On memory exhaustion, %NULL is returned. 608 * 609 * find_or_create_page() may sleep, even if @gfp_flags specifies an 610 * atomic allocation! 611 */ 612 static inline struct page *find_or_create_page(struct address_space *mapping, 613 pgoff_t index, gfp_t gfp_mask) 614 { 615 return pagecache_get_page(mapping, index, 616 FGP_LOCK|FGP_ACCESSED|FGP_CREAT, 617 gfp_mask); 618 } 619 620 /** 621 * grab_cache_page_nowait - returns locked page at given index in given cache 622 * @mapping: target address_space 623 * @index: the page index 624 * 625 * Same as grab_cache_page(), but do not wait if the page is unavailable. 626 * This is intended for speculative data generators, where the data can 627 * be regenerated if the page couldn't be grabbed. This routine should 628 * be safe to call while holding the lock for another page. 629 * 630 * Clear __GFP_FS when allocating the page to avoid recursion into the fs 631 * and deadlock against the caller's locked page. 632 */ 633 static inline struct page *grab_cache_page_nowait(struct address_space *mapping, 634 pgoff_t index) 635 { 636 return pagecache_get_page(mapping, index, 637 FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT, 638 mapping_gfp_mask(mapping)); 639 } 640 641 #define swapcache_index(folio) __page_file_index(&(folio)->page) 642 643 /** 644 * folio_index - File index of a folio. 645 * @folio: The folio. 646 * 647 * For a folio which is either in the page cache or the swap cache, 648 * return its index within the address_space it belongs to. If you know 649 * the page is definitely in the page cache, you can look at the folio's 650 * index directly. 651 * 652 * Return: The index (offset in units of pages) of a folio in its file. 653 */ 654 static inline pgoff_t folio_index(struct folio *folio) 655 { 656 if (unlikely(folio_test_swapcache(folio))) 657 return swapcache_index(folio); 658 return folio->index; 659 } 660 661 /** 662 * folio_next_index - Get the index of the next folio. 663 * @folio: The current folio. 664 * 665 * Return: The index of the folio which follows this folio in the file. 666 */ 667 static inline pgoff_t folio_next_index(struct folio *folio) 668 { 669 return folio->index + folio_nr_pages(folio); 670 } 671 672 /** 673 * folio_file_page - The page for a particular index. 674 * @folio: The folio which contains this index. 675 * @index: The index we want to look up. 676 * 677 * Sometimes after looking up a folio in the page cache, we need to 678 * obtain the specific page for an index (eg a page fault). 679 * 680 * Return: The page containing the file data for this index. 681 */ 682 static inline struct page *folio_file_page(struct folio *folio, pgoff_t index) 683 { 684 /* HugeTLBfs indexes the page cache in units of hpage_size */ 685 if (folio_test_hugetlb(folio)) 686 return &folio->page; 687 return folio_page(folio, index & (folio_nr_pages(folio) - 1)); 688 } 689 690 /** 691 * folio_contains - Does this folio contain this index? 692 * @folio: The folio. 693 * @index: The page index within the file. 694 * 695 * Context: The caller should have the page locked in order to prevent 696 * (eg) shmem from moving the page between the page cache and swap cache 697 * and changing its index in the middle of the operation. 698 * Return: true or false. 699 */ 700 static inline bool folio_contains(struct folio *folio, pgoff_t index) 701 { 702 /* HugeTLBfs indexes the page cache in units of hpage_size */ 703 if (folio_test_hugetlb(folio)) 704 return folio->index == index; 705 return index - folio_index(folio) < folio_nr_pages(folio); 706 } 707 708 /* 709 * Given the page we found in the page cache, return the page corresponding 710 * to this index in the file 711 */ 712 static inline struct page *find_subpage(struct page *head, pgoff_t index) 713 { 714 /* HugeTLBfs wants the head page regardless */ 715 if (PageHuge(head)) 716 return head; 717 718 return head + (index & (thp_nr_pages(head) - 1)); 719 } 720 721 unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, 722 pgoff_t end, unsigned int nr_pages, 723 struct page **pages); 724 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, 725 unsigned int nr_pages, struct page **pages); 726 unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, 727 pgoff_t end, xa_mark_t tag, unsigned int nr_pages, 728 struct page **pages); 729 static inline unsigned find_get_pages_tag(struct address_space *mapping, 730 pgoff_t *index, xa_mark_t tag, unsigned int nr_pages, 731 struct page **pages) 732 { 733 return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag, 734 nr_pages, pages); 735 } 736 737 struct page *grab_cache_page_write_begin(struct address_space *mapping, 738 pgoff_t index, unsigned flags); 739 740 /* 741 * Returns locked page at given index in given cache, creating it if needed. 742 */ 743 static inline struct page *grab_cache_page(struct address_space *mapping, 744 pgoff_t index) 745 { 746 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); 747 } 748 749 struct folio *read_cache_folio(struct address_space *, pgoff_t index, 750 filler_t *filler, void *data); 751 struct page *read_cache_page(struct address_space *, pgoff_t index, 752 filler_t *filler, void *data); 753 extern struct page * read_cache_page_gfp(struct address_space *mapping, 754 pgoff_t index, gfp_t gfp_mask); 755 756 static inline struct page *read_mapping_page(struct address_space *mapping, 757 pgoff_t index, struct file *file) 758 { 759 return read_cache_page(mapping, index, NULL, file); 760 } 761 762 static inline struct folio *read_mapping_folio(struct address_space *mapping, 763 pgoff_t index, struct file *file) 764 { 765 return read_cache_folio(mapping, index, NULL, file); 766 } 767 768 /* 769 * Get index of the page within radix-tree (but not for hugetlb pages). 770 * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE) 771 */ 772 static inline pgoff_t page_to_index(struct page *page) 773 { 774 struct page *head; 775 776 if (likely(!PageTransTail(page))) 777 return page->index; 778 779 head = compound_head(page); 780 /* 781 * We don't initialize ->index for tail pages: calculate based on 782 * head page 783 */ 784 return head->index + page - head; 785 } 786 787 extern pgoff_t hugetlb_basepage_index(struct page *page); 788 789 /* 790 * Get the offset in PAGE_SIZE (even for hugetlb pages). 791 * (TODO: hugetlb pages should have ->index in PAGE_SIZE) 792 */ 793 static inline pgoff_t page_to_pgoff(struct page *page) 794 { 795 if (unlikely(PageHuge(page))) 796 return hugetlb_basepage_index(page); 797 return page_to_index(page); 798 } 799 800 /* 801 * Return byte-offset into filesystem object for page. 802 */ 803 static inline loff_t page_offset(struct page *page) 804 { 805 return ((loff_t)page->index) << PAGE_SHIFT; 806 } 807 808 static inline loff_t page_file_offset(struct page *page) 809 { 810 return ((loff_t)page_index(page)) << PAGE_SHIFT; 811 } 812 813 /** 814 * folio_pos - Returns the byte position of this folio in its file. 815 * @folio: The folio. 816 */ 817 static inline loff_t folio_pos(struct folio *folio) 818 { 819 return page_offset(&folio->page); 820 } 821 822 /** 823 * folio_file_pos - Returns the byte position of this folio in its file. 824 * @folio: The folio. 825 * 826 * This differs from folio_pos() for folios which belong to a swap file. 827 * NFS is the only filesystem today which needs to use folio_file_pos(). 828 */ 829 static inline loff_t folio_file_pos(struct folio *folio) 830 { 831 return page_file_offset(&folio->page); 832 } 833 834 /* 835 * Get the offset in PAGE_SIZE (even for hugetlb folios). 836 * (TODO: hugetlb folios should have ->index in PAGE_SIZE) 837 */ 838 static inline pgoff_t folio_pgoff(struct folio *folio) 839 { 840 if (unlikely(folio_test_hugetlb(folio))) 841 return hugetlb_basepage_index(&folio->page); 842 return folio->index; 843 } 844 845 extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 846 unsigned long address); 847 848 static inline pgoff_t linear_page_index(struct vm_area_struct *vma, 849 unsigned long address) 850 { 851 pgoff_t pgoff; 852 if (unlikely(is_vm_hugetlb_page(vma))) 853 return linear_hugepage_index(vma, address); 854 pgoff = (address - vma->vm_start) >> PAGE_SHIFT; 855 pgoff += vma->vm_pgoff; 856 return pgoff; 857 } 858 859 struct wait_page_key { 860 struct folio *folio; 861 int bit_nr; 862 int page_match; 863 }; 864 865 struct wait_page_queue { 866 struct folio *folio; 867 int bit_nr; 868 wait_queue_entry_t wait; 869 }; 870 871 static inline bool wake_page_match(struct wait_page_queue *wait_page, 872 struct wait_page_key *key) 873 { 874 if (wait_page->folio != key->folio) 875 return false; 876 key->page_match = 1; 877 878 if (wait_page->bit_nr != key->bit_nr) 879 return false; 880 881 return true; 882 } 883 884 void __folio_lock(struct folio *folio); 885 int __folio_lock_killable(struct folio *folio); 886 bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, 887 unsigned int flags); 888 void unlock_page(struct page *page); 889 void folio_unlock(struct folio *folio); 890 891 static inline bool folio_trylock(struct folio *folio) 892 { 893 return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0))); 894 } 895 896 /* 897 * Return true if the page was successfully locked 898 */ 899 static inline int trylock_page(struct page *page) 900 { 901 return folio_trylock(page_folio(page)); 902 } 903 904 static inline void folio_lock(struct folio *folio) 905 { 906 might_sleep(); 907 if (!folio_trylock(folio)) 908 __folio_lock(folio); 909 } 910 911 /* 912 * lock_page may only be called if we have the page's inode pinned. 913 */ 914 static inline void lock_page(struct page *page) 915 { 916 struct folio *folio; 917 might_sleep(); 918 919 folio = page_folio(page); 920 if (!folio_trylock(folio)) 921 __folio_lock(folio); 922 } 923 924 static inline int folio_lock_killable(struct folio *folio) 925 { 926 might_sleep(); 927 if (!folio_trylock(folio)) 928 return __folio_lock_killable(folio); 929 return 0; 930 } 931 932 /* 933 * lock_page_killable is like lock_page but can be interrupted by fatal 934 * signals. It returns 0 if it locked the page and -EINTR if it was 935 * killed while waiting. 936 */ 937 static inline int lock_page_killable(struct page *page) 938 { 939 return folio_lock_killable(page_folio(page)); 940 } 941 942 /* 943 * lock_page_or_retry - Lock the page, unless this would block and the 944 * caller indicated that it can handle a retry. 945 * 946 * Return value and mmap_lock implications depend on flags; see 947 * __folio_lock_or_retry(). 948 */ 949 static inline bool lock_page_or_retry(struct page *page, struct mm_struct *mm, 950 unsigned int flags) 951 { 952 struct folio *folio; 953 might_sleep(); 954 955 folio = page_folio(page); 956 return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags); 957 } 958 959 /* 960 * This is exported only for folio_wait_locked/folio_wait_writeback, etc., 961 * and should not be used directly. 962 */ 963 void folio_wait_bit(struct folio *folio, int bit_nr); 964 int folio_wait_bit_killable(struct folio *folio, int bit_nr); 965 966 /* 967 * Wait for a folio to be unlocked. 968 * 969 * This must be called with the caller "holding" the folio, 970 * ie with increased "page->count" so that the folio won't 971 * go away during the wait.. 972 */ 973 static inline void folio_wait_locked(struct folio *folio) 974 { 975 if (folio_test_locked(folio)) 976 folio_wait_bit(folio, PG_locked); 977 } 978 979 static inline int folio_wait_locked_killable(struct folio *folio) 980 { 981 if (!folio_test_locked(folio)) 982 return 0; 983 return folio_wait_bit_killable(folio, PG_locked); 984 } 985 986 static inline void wait_on_page_locked(struct page *page) 987 { 988 folio_wait_locked(page_folio(page)); 989 } 990 991 static inline int wait_on_page_locked_killable(struct page *page) 992 { 993 return folio_wait_locked_killable(page_folio(page)); 994 } 995 996 int folio_put_wait_locked(struct folio *folio, int state); 997 void wait_on_page_writeback(struct page *page); 998 void folio_wait_writeback(struct folio *folio); 999 int folio_wait_writeback_killable(struct folio *folio); 1000 void end_page_writeback(struct page *page); 1001 void folio_end_writeback(struct folio *folio); 1002 void wait_for_stable_page(struct page *page); 1003 void folio_wait_stable(struct folio *folio); 1004 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn); 1005 static inline void __set_page_dirty(struct page *page, 1006 struct address_space *mapping, int warn) 1007 { 1008 __folio_mark_dirty(page_folio(page), mapping, warn); 1009 } 1010 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb); 1011 void __folio_cancel_dirty(struct folio *folio); 1012 static inline void folio_cancel_dirty(struct folio *folio) 1013 { 1014 /* Avoid atomic ops, locking, etc. when not actually needed. */ 1015 if (folio_test_dirty(folio)) 1016 __folio_cancel_dirty(folio); 1017 } 1018 static inline void cancel_dirty_page(struct page *page) 1019 { 1020 folio_cancel_dirty(page_folio(page)); 1021 } 1022 bool folio_clear_dirty_for_io(struct folio *folio); 1023 bool clear_page_dirty_for_io(struct page *page); 1024 void folio_invalidate(struct folio *folio, size_t offset, size_t length); 1025 int __must_check folio_write_one(struct folio *folio); 1026 static inline int __must_check write_one_page(struct page *page) 1027 { 1028 return folio_write_one(page_folio(page)); 1029 } 1030 1031 int __set_page_dirty_nobuffers(struct page *page); 1032 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio); 1033 1034 void page_endio(struct page *page, bool is_write, int err); 1035 1036 void folio_end_private_2(struct folio *folio); 1037 void folio_wait_private_2(struct folio *folio); 1038 int folio_wait_private_2_killable(struct folio *folio); 1039 1040 /* 1041 * Add an arbitrary waiter to a page's wait queue 1042 */ 1043 void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter); 1044 1045 /* 1046 * Fault in userspace address range. 1047 */ 1048 size_t fault_in_writeable(char __user *uaddr, size_t size); 1049 size_t fault_in_safe_writeable(const char __user *uaddr, size_t size); 1050 size_t fault_in_readable(const char __user *uaddr, size_t size); 1051 1052 int add_to_page_cache_locked(struct page *page, struct address_space *mapping, 1053 pgoff_t index, gfp_t gfp); 1054 int add_to_page_cache_lru(struct page *page, struct address_space *mapping, 1055 pgoff_t index, gfp_t gfp); 1056 int filemap_add_folio(struct address_space *mapping, struct folio *folio, 1057 pgoff_t index, gfp_t gfp); 1058 void filemap_remove_folio(struct folio *folio); 1059 void delete_from_page_cache(struct page *page); 1060 void __filemap_remove_folio(struct folio *folio, void *shadow); 1061 static inline void __delete_from_page_cache(struct page *page, void *shadow) 1062 { 1063 __filemap_remove_folio(page_folio(page), shadow); 1064 } 1065 void replace_page_cache_page(struct page *old, struct page *new); 1066 void delete_from_page_cache_batch(struct address_space *mapping, 1067 struct folio_batch *fbatch); 1068 int try_to_release_page(struct page *page, gfp_t gfp); 1069 bool filemap_release_folio(struct folio *folio, gfp_t gfp); 1070 loff_t mapping_seek_hole_data(struct address_space *, loff_t start, loff_t end, 1071 int whence); 1072 1073 /* 1074 * Like add_to_page_cache_locked, but used to add newly allocated pages: 1075 * the page is new, so we can just run __SetPageLocked() against it. 1076 */ 1077 static inline int add_to_page_cache(struct page *page, 1078 struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) 1079 { 1080 int error; 1081 1082 __SetPageLocked(page); 1083 error = add_to_page_cache_locked(page, mapping, offset, gfp_mask); 1084 if (unlikely(error)) 1085 __ClearPageLocked(page); 1086 return error; 1087 } 1088 1089 /* Must be non-static for BPF error injection */ 1090 int __filemap_add_folio(struct address_space *mapping, struct folio *folio, 1091 pgoff_t index, gfp_t gfp, void **shadowp); 1092 1093 bool filemap_range_has_writeback(struct address_space *mapping, 1094 loff_t start_byte, loff_t end_byte); 1095 1096 /** 1097 * filemap_range_needs_writeback - check if range potentially needs writeback 1098 * @mapping: address space within which to check 1099 * @start_byte: offset in bytes where the range starts 1100 * @end_byte: offset in bytes where the range ends (inclusive) 1101 * 1102 * Find at least one page in the range supplied, usually used to check if 1103 * direct writing in this range will trigger a writeback. Used by O_DIRECT 1104 * read/write with IOCB_NOWAIT, to see if the caller needs to do 1105 * filemap_write_and_wait_range() before proceeding. 1106 * 1107 * Return: %true if the caller should do filemap_write_and_wait_range() before 1108 * doing O_DIRECT to a page in this range, %false otherwise. 1109 */ 1110 static inline bool filemap_range_needs_writeback(struct address_space *mapping, 1111 loff_t start_byte, 1112 loff_t end_byte) 1113 { 1114 if (!mapping->nrpages) 1115 return false; 1116 if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && 1117 !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) 1118 return false; 1119 return filemap_range_has_writeback(mapping, start_byte, end_byte); 1120 } 1121 1122 /** 1123 * struct readahead_control - Describes a readahead request. 1124 * 1125 * A readahead request is for consecutive pages. Filesystems which 1126 * implement the ->readahead method should call readahead_page() or 1127 * readahead_page_batch() in a loop and attempt to start I/O against 1128 * each page in the request. 1129 * 1130 * Most of the fields in this struct are private and should be accessed 1131 * by the functions below. 1132 * 1133 * @file: The file, used primarily by network filesystems for authentication. 1134 * May be NULL if invoked internally by the filesystem. 1135 * @mapping: Readahead this filesystem object. 1136 * @ra: File readahead state. May be NULL. 1137 */ 1138 struct readahead_control { 1139 struct file *file; 1140 struct address_space *mapping; 1141 struct file_ra_state *ra; 1142 /* private: use the readahead_* accessors instead */ 1143 pgoff_t _index; 1144 unsigned int _nr_pages; 1145 unsigned int _batch_count; 1146 }; 1147 1148 #define DEFINE_READAHEAD(ractl, f, r, m, i) \ 1149 struct readahead_control ractl = { \ 1150 .file = f, \ 1151 .mapping = m, \ 1152 .ra = r, \ 1153 ._index = i, \ 1154 } 1155 1156 #define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE) 1157 1158 void page_cache_ra_unbounded(struct readahead_control *, 1159 unsigned long nr_to_read, unsigned long lookahead_count); 1160 void page_cache_sync_ra(struct readahead_control *, unsigned long req_count); 1161 void page_cache_async_ra(struct readahead_control *, struct folio *, 1162 unsigned long req_count); 1163 void readahead_expand(struct readahead_control *ractl, 1164 loff_t new_start, size_t new_len); 1165 1166 /** 1167 * page_cache_sync_readahead - generic file readahead 1168 * @mapping: address_space which holds the pagecache and I/O vectors 1169 * @ra: file_ra_state which holds the readahead state 1170 * @file: Used by the filesystem for authentication. 1171 * @index: Index of first page to be read. 1172 * @req_count: Total number of pages being read by the caller. 1173 * 1174 * page_cache_sync_readahead() should be called when a cache miss happened: 1175 * it will submit the read. The readahead logic may decide to piggyback more 1176 * pages onto the read request if access patterns suggest it will improve 1177 * performance. 1178 */ 1179 static inline 1180 void page_cache_sync_readahead(struct address_space *mapping, 1181 struct file_ra_state *ra, struct file *file, pgoff_t index, 1182 unsigned long req_count) 1183 { 1184 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1185 page_cache_sync_ra(&ractl, req_count); 1186 } 1187 1188 /** 1189 * page_cache_async_readahead - file readahead for marked pages 1190 * @mapping: address_space which holds the pagecache and I/O vectors 1191 * @ra: file_ra_state which holds the readahead state 1192 * @file: Used by the filesystem for authentication. 1193 * @page: The page at @index which triggered the readahead call. 1194 * @index: Index of first page to be read. 1195 * @req_count: Total number of pages being read by the caller. 1196 * 1197 * page_cache_async_readahead() should be called when a page is used which 1198 * is marked as PageReadahead; this is a marker to suggest that the application 1199 * has used up enough of the readahead window that we should start pulling in 1200 * more pages. 1201 */ 1202 static inline 1203 void page_cache_async_readahead(struct address_space *mapping, 1204 struct file_ra_state *ra, struct file *file, 1205 struct page *page, pgoff_t index, unsigned long req_count) 1206 { 1207 DEFINE_READAHEAD(ractl, file, ra, mapping, index); 1208 page_cache_async_ra(&ractl, page_folio(page), req_count); 1209 } 1210 1211 static inline struct folio *__readahead_folio(struct readahead_control *ractl) 1212 { 1213 struct folio *folio; 1214 1215 BUG_ON(ractl->_batch_count > ractl->_nr_pages); 1216 ractl->_nr_pages -= ractl->_batch_count; 1217 ractl->_index += ractl->_batch_count; 1218 1219 if (!ractl->_nr_pages) { 1220 ractl->_batch_count = 0; 1221 return NULL; 1222 } 1223 1224 folio = xa_load(&ractl->mapping->i_pages, ractl->_index); 1225 VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); 1226 ractl->_batch_count = folio_nr_pages(folio); 1227 1228 return folio; 1229 } 1230 1231 /** 1232 * readahead_page - Get the next page to read. 1233 * @ractl: The current readahead request. 1234 * 1235 * Context: The page is locked and has an elevated refcount. The caller 1236 * should decreases the refcount once the page has been submitted for I/O 1237 * and unlock the page once all I/O to that page has completed. 1238 * Return: A pointer to the next page, or %NULL if we are done. 1239 */ 1240 static inline struct page *readahead_page(struct readahead_control *ractl) 1241 { 1242 struct folio *folio = __readahead_folio(ractl); 1243 1244 return &folio->page; 1245 } 1246 1247 /** 1248 * readahead_folio - Get the next folio to read. 1249 * @ractl: The current readahead request. 1250 * 1251 * Context: The folio is locked. The caller should unlock the folio once 1252 * all I/O to that folio has completed. 1253 * Return: A pointer to the next folio, or %NULL if we are done. 1254 */ 1255 static inline struct folio *readahead_folio(struct readahead_control *ractl) 1256 { 1257 struct folio *folio = __readahead_folio(ractl); 1258 1259 if (folio) 1260 folio_put(folio); 1261 return folio; 1262 } 1263 1264 static inline unsigned int __readahead_batch(struct readahead_control *rac, 1265 struct page **array, unsigned int array_sz) 1266 { 1267 unsigned int i = 0; 1268 XA_STATE(xas, &rac->mapping->i_pages, 0); 1269 struct page *page; 1270 1271 BUG_ON(rac->_batch_count > rac->_nr_pages); 1272 rac->_nr_pages -= rac->_batch_count; 1273 rac->_index += rac->_batch_count; 1274 rac->_batch_count = 0; 1275 1276 xas_set(&xas, rac->_index); 1277 rcu_read_lock(); 1278 xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) { 1279 if (xas_retry(&xas, page)) 1280 continue; 1281 VM_BUG_ON_PAGE(!PageLocked(page), page); 1282 VM_BUG_ON_PAGE(PageTail(page), page); 1283 array[i++] = page; 1284 rac->_batch_count += thp_nr_pages(page); 1285 if (i == array_sz) 1286 break; 1287 } 1288 rcu_read_unlock(); 1289 1290 return i; 1291 } 1292 1293 /** 1294 * readahead_page_batch - Get a batch of pages to read. 1295 * @rac: The current readahead request. 1296 * @array: An array of pointers to struct page. 1297 * 1298 * Context: The pages are locked and have an elevated refcount. The caller 1299 * should decreases the refcount once the page has been submitted for I/O 1300 * and unlock the page once all I/O to that page has completed. 1301 * Return: The number of pages placed in the array. 0 indicates the request 1302 * is complete. 1303 */ 1304 #define readahead_page_batch(rac, array) \ 1305 __readahead_batch(rac, array, ARRAY_SIZE(array)) 1306 1307 /** 1308 * readahead_pos - The byte offset into the file of this readahead request. 1309 * @rac: The readahead request. 1310 */ 1311 static inline loff_t readahead_pos(struct readahead_control *rac) 1312 { 1313 return (loff_t)rac->_index * PAGE_SIZE; 1314 } 1315 1316 /** 1317 * readahead_length - The number of bytes in this readahead request. 1318 * @rac: The readahead request. 1319 */ 1320 static inline size_t readahead_length(struct readahead_control *rac) 1321 { 1322 return rac->_nr_pages * PAGE_SIZE; 1323 } 1324 1325 /** 1326 * readahead_index - The index of the first page in this readahead request. 1327 * @rac: The readahead request. 1328 */ 1329 static inline pgoff_t readahead_index(struct readahead_control *rac) 1330 { 1331 return rac->_index; 1332 } 1333 1334 /** 1335 * readahead_count - The number of pages in this readahead request. 1336 * @rac: The readahead request. 1337 */ 1338 static inline unsigned int readahead_count(struct readahead_control *rac) 1339 { 1340 return rac->_nr_pages; 1341 } 1342 1343 /** 1344 * readahead_batch_length - The number of bytes in the current batch. 1345 * @rac: The readahead request. 1346 */ 1347 static inline size_t readahead_batch_length(struct readahead_control *rac) 1348 { 1349 return rac->_batch_count * PAGE_SIZE; 1350 } 1351 1352 static inline unsigned long dir_pages(struct inode *inode) 1353 { 1354 return (unsigned long)(inode->i_size + PAGE_SIZE - 1) >> 1355 PAGE_SHIFT; 1356 } 1357 1358 /** 1359 * folio_mkwrite_check_truncate - check if folio was truncated 1360 * @folio: the folio to check 1361 * @inode: the inode to check the folio against 1362 * 1363 * Return: the number of bytes in the folio up to EOF, 1364 * or -EFAULT if the folio was truncated. 1365 */ 1366 static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio, 1367 struct inode *inode) 1368 { 1369 loff_t size = i_size_read(inode); 1370 pgoff_t index = size >> PAGE_SHIFT; 1371 size_t offset = offset_in_folio(folio, size); 1372 1373 if (!folio->mapping) 1374 return -EFAULT; 1375 1376 /* folio is wholly inside EOF */ 1377 if (folio_next_index(folio) - 1 < index) 1378 return folio_size(folio); 1379 /* folio is wholly past EOF */ 1380 if (folio->index > index || !offset) 1381 return -EFAULT; 1382 /* folio is partially inside EOF */ 1383 return offset; 1384 } 1385 1386 /** 1387 * page_mkwrite_check_truncate - check if page was truncated 1388 * @page: the page to check 1389 * @inode: the inode to check the page against 1390 * 1391 * Returns the number of bytes in the page up to EOF, 1392 * or -EFAULT if the page was truncated. 1393 */ 1394 static inline int page_mkwrite_check_truncate(struct page *page, 1395 struct inode *inode) 1396 { 1397 loff_t size = i_size_read(inode); 1398 pgoff_t index = size >> PAGE_SHIFT; 1399 int offset = offset_in_page(size); 1400 1401 if (page->mapping != inode->i_mapping) 1402 return -EFAULT; 1403 1404 /* page is wholly inside EOF */ 1405 if (page->index < index) 1406 return PAGE_SIZE; 1407 /* page is wholly past EOF */ 1408 if (page->index > index || !offset) 1409 return -EFAULT; 1410 /* page is partially inside EOF */ 1411 return offset; 1412 } 1413 1414 /** 1415 * i_blocks_per_folio - How many blocks fit in this folio. 1416 * @inode: The inode which contains the blocks. 1417 * @folio: The folio. 1418 * 1419 * If the block size is larger than the size of this folio, return zero. 1420 * 1421 * Context: The caller should hold a refcount on the folio to prevent it 1422 * from being split. 1423 * Return: The number of filesystem blocks covered by this folio. 1424 */ 1425 static inline 1426 unsigned int i_blocks_per_folio(struct inode *inode, struct folio *folio) 1427 { 1428 return folio_size(folio) >> inode->i_blkbits; 1429 } 1430 1431 static inline 1432 unsigned int i_blocks_per_page(struct inode *inode, struct page *page) 1433 { 1434 return i_blocks_per_folio(inode, page_folio(page)); 1435 } 1436 #endif /* _LINUX_PAGEMAP_H */ 1437